Liquid feed arrangement



Jan. 5, 1965 J. N. SAUNDERS 3,164,162

LIQUID FEED ARRANGEMENT Filed Sept. 6. 1961 v mveuron: JA'CA NORMA/V SA UNDfRS ,g ilwwz /a United States Patent Ofiice 3,164,162 Patented Jan. 5, 1965 This invention concerns liquid feed arrangements, and especially, but not exclusively, relates to such arrangements'in heating systems which, in operat1on, are pressurized to enable the circulating liquid medium, usually water, to be used at a temperature above its normal boiling point (i.e. its boiling point at atmospheric pressure) and which, in addition to a high pressure cylinder, have a low pressure container for accommodating the expansion liquid. Such systems are hereinafter called heating systems of the type referred to.

In the specification of our prior British Patent No. 814,729 we have described a heating system of the type referred to, using water, in which the low pressurecontainer is closed, and in which a space above the liquid therein is occupied by an inert gas, preferably nitrogen, at the desired low pressure, or within a desired low pressure range. The main advantages of such an arrangement are that the high pressure cylinder may be of small dimensions, the less costly low pressure cylinder providing the necessary volume to accommodate the expansion liquid, and that contamination, and especially the absorption of oxygen by the water is largely prevented. Such absorption, or oxygenation, is always likely to occur in liquid feed arrangements where disturbed liquid surfaces occur in an environment in which oxygen is present. However, such prior arrangement has disadvantages. Thus, to maintain the pressure of the inert gas within a suitable range, either the low pressure vessel must have a volume substantially greater than that of the expansion water, so as to allow of a gas cushion of considerable volume, or, means must be provided for exhausting and replenishing nitrogen in amounts which may be considerable. The principal object of the present invention is to avoid these disadvantages in heating systems of the type referred to, and the invention is based on the appreciation that the most serious cause of oxygenation arises from the repeated introduction to the low pressure vessel of water from the high pressure side of the installation, and that localized means can be provided for the prevention of such oxygenation.

Thus, according to the broadest aspect of the present invention, in a liquid feed arrangement wherein liquid is fed to a container or the like in turbulent or agitated manner, we provide a localized enclosure for the region of turbulence or agitation, means for maintaining an atmosphere of inert gas within such enclosure, and means for replenishing said gas as necessary to maintain the pressure thereof within given limits.

According to a more particular feature of the present invention, We provide, in a heating system of the type referred to,.a low pressure container of generally open construction, and means enclosing a volume above a localized area of the surface of the low pressure liquid, the said means being adapted to accommodate an inert gas and having inlet means for expansion liquid, the said volume being small relative to the volume of the low pressure container. Preferably the means enclosing a volume above a localized area of the said surface also has associated therewith means for replenishing said gas to maintain the pressure thereof within desired limits.

The invention will now be described further by way of example only, with reference to the single figure of the accompanying drawings which illustrates diagrammatically one embodiment thereof.

Referring now to the drawings the low pressure container of the heating system substantially as described in our prior British Patent No. 814,729 is constructed in accordance with the present invention. Thus we provide, in a heating system of the type referred to a heating circuit 11 having a boiler 12, a high pressure container 13 connected to said circuit 11 through a feed line 14 having an isolation valve 14a therein, and a low pressure container 15. The low pressure container 15 is constructed basically as an open vessel of a size little more than adequate to accommodate the maximum amount of expansion water that the system will generate and in the container 15 is disposed an inverted tubular pressure vessel 16 having an open end 16a below the minimum liquid level (near the bottom of the low pressure container and maintained by an external water supply 17 feeding to the vessel 16 under the control of a ball valve 18), and a closed upper end 1611 extending a little above the upper end of the low pressure container. The diameter of the pressure vessel 16 is such that only a very localized area 19' of the total liquid surface 19 lies therein, whereby it follows that the volume enclosed thereby is small relative to the volume of the low pressure container. The space 20 within the vessel 16 and above the liquid surface 19' is initially filled with air and loss of gas by absorption in the water is made up by admission of nitrogen to space 20. Nitrogen is applied to the space 20 from a high pressure nitrogen cylinder 21, the connecting pipeline 22 including pressure reducing valves 23, 24- therein.

The connections between the high pressure container 13 and the lower pressure container 15 are such that upon expansion of the heating liquid, the expansion volume thereof flows to the low pressure container 15 through member 16, whilst on cooling the necessary make-up in the high pressure container 13 is supplied by flow of liquid from the low pressure container. The connections comprise a pipe-line 25 between the lower part of the high pressure container 13 and the top of the tubular pressure vessel 16 for the passage of expansion volume and a return feed-line 26 from the container 15 to the high pressure container. An isolation valve 27 and a transfer valve 28 are included in the pipe-line 25, the latter being automatically adjusted under the control of a pressure sensing device 29 in the pipe-line. A loop 30 is provided between the top of the container 13 and the pipe-line 25, such loop 30 including an isolating valve 31.

The return feed-line 26 includes two pumps 32a, 32b disposed in parallel relationship and each having associated isolator valves 33a, 33b, filters 34a, 34b and one way valves 35a, 35b, such pumps 32a, 32b being adapted to be operated under the control of the pressure sensing device 29.

The requisite high pressure in the high pressure container 13 is maintained by feeding nitrogen from the cylinder 21 through connecting piping 36 to the top of the container, such piping including a pressure reducing valve 37.

The operation of the system such as has been described will be readily apparent to one skilled in the art, it being appreciated that the isolator valves 14a, 27 and either' 33a or 33b will normally be open and valve 31 closed.

It will be readily appreciated that the passage of expansion water to the low pressure container 15, or more specifically to the tubular vessel 16, through the pipe-line 25 is in an atmosphere of inert gas, and therefore, the main source of oxygenation is avoided; and that the volume of nitrogen expended in maintaining the required pressure in the tubular pressure vessel 16 will be small compared with that which would be necessary in a closed 3 low pressure container of a size commensurate with the volume of expansion water. Furthermore, make-up water from the water supply 17 is also applied in an atmosphere of inert gas. g

The invention is not limited to the specific details of the embodiment just described. For example, the tubular pressure member could be disposed Outside the low pressure container with a pipe connection between its base and the base of the latter. Further, the ball valve arrangement for providing make-up liquid could itself be provided with means according to the invention to prevent oxygenation.

It is also possible to obtain, at least, in part, the advantage of the present arrangement without initially charging the interior of the inverted tubular member with nitrogen, and accepting such contamination as is consequent upon oxygenation in respect of the small quantity of air present. It is thought that the nitrogen in the tubular member would be augmented by nitrogen absorbed in the high pressure system and released in the lower pressure region in the tubular member, such transfer offsetting, to some extent, pressure fluctuations in the tubular member.

Furthermore, the invention is not restricted to application in the exact context of the embodiment specifically described since alternative applications will be apparent to one skilled in the art. For example an analogous arrangement may be used with advantage to prevent oxygenation or aeration due to condensate return lines in steam systems.

I claim:

1. In a liquid feed arrangement wherein liquid is fed to a container or the like in a manner which causes the surface of the liquid in the container to become turbulent or agitated, a localized enclosure defining a confined space above the region of turbulence or agitation, means for maintaining an atmosphere of gas within said confined space, said gas being chemically inert in relation to the material of the enclosure and any other part of the liquid feed arrangement with which such gas, when absorbed by the liquid, comes into contact, and means for replenishing said gas as necessary to maintain the pressure thereof within given limits.

2. Aliquidfeed arrangement of the type referred to including a low pressure cylinder of generally open construction, and space defining means enclosing a confined volume above a localized area of the surface of low pressure liquid in said cylinder, the said means being adapted to accommodate a gas chemically inert in relation to the material of any parts of the liquid feed arrangement with such gas, when absorbed by the liquid, comes into contact, inlet means associated with the said space defining means whereby expansion liquid may be applied thereto, the said volume being small relative to the volume of the low pressure cylinder.

3. A liquid feed arrangement as claimed in claim 2 wherein the means enclosing a volume above a localized area of the said surface also has means for replenishing said gas to maintain the pressure thereof within desired limits. 7

4. In a liquid feed arrangement of the type referred to an arrangement comprising a low pressure cylinder of generally open construction, a tubular member having an open lower end disposed below the minimum liquid surface level within the low pressure cylinder and having a closed upper end enclosing a confined volume above a localized area of said liquid surface, and inlet means whereby expansion liquid may be applied to the tubular member, the said tubular member being adapted to accommodate a gas chemically inert in relation to the material of any parts of the liquid feed arrangement with which such gas, when absorbed by the liquid, comes into contact and the said volume being small relative to the volume of the low pressure cylinder.

5. In a liquid feed arrangement of the type referred to an arrangement comprising a low pressure cylinder of generally open construction, a tubular member having an open lower end disposed below the minimum liquid surface level within the low pressure cylinder and having a closed upper end enclosing a confined volume above a localized area of said liquid surface, inlet means whereby expansion liquid may be applied to the tubular member, and means for replenishing the gas to maintain the pressure thereof within desired limits, the said tubular member being adapted to accommodate a gas chemically inert in relation to the material of any parts of the liquid feed arrangement with which such gas, when absorbed by the liquid, comes into contact and the said volume being small relative to the volume of the low pressure cylinder.

6. A liquid feed arrangement of the type referred to including a low pressure cylinder of generally open construction, an open upper end to said cylinder, an inverted tubular member disposed in said low pressure cylinder, the said member having an open lower end thereof located below the minimum liquid level in the low pressure cylinder and a closed upper end slightly above the corresponding end of the said cylinder defining a confined gas volume space, inlet means associated with said tubular member adapted to apply expansion liquid to said confined space. and means whereby a gas may be applied to said confined space thus to maintain the gas pressure therein within desired limits, said gas being chemically inert in relation to the material of the tubular member and any other part of the liquid feed arrangement with which such gas. when absorbed by the liquid, comes into contact, the said tubular member enclosing said confined space above a localized area of the liquid surface which is small relative to the volume of the low pressure cylinder.

7. A liquid feed arangement as claimed in claim 6 including means for maintaining a minimum liquid level in the low pressure cylinder.

8. A liquid feed arrangement as claimed in claim 7 in which the said means includes a float actuated ball valve.

9. In a liquid feed arrangement of the type referred to an arangement comprising a low pressure cylinder of generally open construction, a tubular member having an open lower end disposed below the minimum liquid surface level within the low pressure cylinder and a closed upper end enclosing a confined space above a localized area of said liquid surface, inlet means whereby expansion liquid may be applied to the confined space region or" said tubular member, and including means for maintaining a minimum liquid level in the low pressure cylinder, the said tubular member being adapted to accommodate a gas chemically inert in relation to the material of any parts of the liquid feed arrangement with which such gas, when absorbed by the liquid, comes into contact and the said volume being small relative to the volume of the low pressure cylinder.

10. In a liquid feed arrangement of the type having a low pressure container for holding a supply of the liquid medium to compensate for liquid volume changes in high pressure components of the liquid feed arrangement, and an inlet disposed above the liquid level in said container through which expansion liquid from said high pressure components enters said container and in so doing agitates the surface of the liquid in said container, the improvement which consists in an enclosure surrounding a small portion of the surface area of the liquid in said container and defining a confined gas volume space above the liquid, the liquid-filled portion of said enclosure communicating with the liquid volume region of said container to permit free flow of liquid from said enclosure to said container, said inlet being arranged within the confined gaseous volume space of said enclosure so that expansion liquid entering said container first contacts the portion of the liquid surface area surrounded by said enclosure, and means for maintaining within said gaseous volume space an atmosphere of a gas chemically inert in relation to the material of the enclosure and any other part of the liquid feed arrangement with which such gas, when absorbed by the liquid, comes into contact whereby agitation of the liquid surface within said enclosure by expansion liquid entering through said inlet does not cause harmful absorption of any gas by the liquid.

11. A method of feeding expansion liquid from the high pressure components of a liquid feed arrangement to a liquid-filled low pressure container of the system, comprising the steps of providing a confined atmosphere of a gas chemically inert in relation to the material forming the parts of the liquid feed arrangement with which the gas, when absorbed by the liquid, comes into contact adjacent to and directly above a small portion of the surface area of the liquid in said container, and directing the expansion liquid through said confined atmosphere into said container.

References Cited by the Examiner UNITED STATES PATENTS 580,208 4/97 Cahill 137-591X 1,269,666 6/18 Wheeler 137-209X 1,657,658 1/28 Buford "137-437):

2,638,916 5/53 Scheiwer 1 137 592 FOREIGN PATENTS 1,141,588 3/57 France.

EDWARD J. MICHAEL, Primary Examiner.

WILLIAM F. ODEA, PERCY L. PATRICK, Examiners. 

1. IN A LIQUID FEED ARRANGEMENT WHEREIN LIQUID IS FED TO A CONTAINER OR THE LIKE IN A MANNER WHICH CAUSES THE SURFACE OF THE LIQUID IN THE CONTAINER TO BECOME TURBULENT OR AGITATED, A LOCALIZED ENCLOSURE DEFINING A CONFINED SPACE ABOVE THE REGION OF TURBULENCE OR AGITATION, MEANS FOR MAINTAINING AN ATMOSPHERE OF GAS WITHIN SAID CONFINED SPACE, SAID GAS BEING CHEMICALLY INERT IN RELATION TO THE MATERIAL OF THE ENCLOSURE AND ANY OTHER PART OF THE LIQUID FEED ARRANGEMENT WITH WHICH SUCH GAS, WHEN ABSORBED BY THE LIQUID, COMES INTO CONTACT, AND MEANS FOR REPLENISHING SAID GAS AS NECESSARY TO MAINTAIN THE PRESSURE THEREOF WITHIN GIVEN LIMITS. 